Jaw chuck for machine tools



June 24,1930.

w. BERG JAW CHUCK FOR MACHINE TOOLS Filed Dec. 16. 1927 Patented June 24, 1930 UHTED srrss ATENT oFFica WILHELM BER-Gr, E BIELEFELD, GERMANY J'AW CHUCK FOR IKACHINE TOOLS Application filed December 16, 1927, Serial. No. 240,501, and in Germany January 25, 192?.

This invention relates to the construction The guide-pieces are; formed simply by turnof a jaw chuck specially a chuck with three ing or grinding, and the chuck has cylinjaws for all kind ofmachine-tools and other drical borings which require merely a quite machines. Chucks with radial adjustment simple working.

of the jaws are equipped generally with The round rod may be made of round iron cam-elements, arranged in the chuck pressand needs for sufiicient precision merely to ing against other cams, studs or rollers on be ground. the lower side of the jaws. These elements An embodiment of the invention is illusare at present mounted only at one side, the trated, by way of example, in the accom- 10 free and projecting end touching the cam panying drawing, in which elements. F ig. 1 is a longitudinal section showing Jaw-chucks of this type were suiiicient as the chuck. long as the chucks were not submitted to Fig. 2 is a top-plan-view partly in section. great stress. At the great efiiciency expect- Fig. 3 is a cross-section showing the guide 15 ed from modern machine-tools, especially pieces and the jaws. Y

i when the working of the work is done with Fig. 4 is an enlarged View of cam, roller, high speed, much feed or by several tools and roller bolt supported on both ends by at the same time, the clamping power of the two bearings'of the guide-piece, and Fig. 5 jaw chuck is as well known no longer sufiiis a detail View. I

29 cient. .Vhen considerable powers occur, the The chuck consists of-a body 1 in which supporting parts mounted at one side, bend a worm-wheel 2 is located which is rotated or break off ,by a worm? The worm-wheel 2 carries As on the other hand the force of the the cams 4c. The power movement of the workman to clamp the chuck is limited and 1 11 4 Will e tra smitted by the roller 25 cannot be increased, this human clamping The 1 r5i P l'h W eIl tW b arings force has to be better utilized so that the and 8 0f the roller belt The O clamping effect of the chuck becomes greater. i gs 7 and 8 0 the r r b l 6 are p r s This object is obtained, according to the f the guide pieces supporting the roller invention, by supporting the roller bolt on T0 ep the r l 5 n p s t n, One

both ends. The roller itself is placed beeIIdVOf the r l er b l 6 is formed as a 001- tween these two roller bolt bearings, trans- -7- V j i mitting so the power movement of the cams Th r llers are preferably arranged in by the roller, the roller bolt, the two roller P n 011 eileh e f the 0am (Figs. 2

bolt-bearings, the guide piece on the jaws. and 4), 9 t t1'anSm1sS 10nS great Power To keep the roller in position, one end of are P03311916 111 Q Qhrectlons of 'm the roller bolt is formed as a collar. By this m e elemplngv J w 10 Test n the design the diameter of the roller bolt is kept fl ppe p e e Pound rods 9 and re very Small bending breaking of connected with these rods by screws 11. roller bolt has become impossible, therefore Order to reduce h baa-k lash of the friction is reduced to the smallest chuck as. much as posslble and ak up amount possible with the result: the limited Well Worm-pressure the Worm-31S human ower ivin the m ximum clam Hal-1 m bushes 12 and The bush P b b p 13 may have an adjustable counter-pressure lng power on the workpiece.

screw 14: by means of which the bearing for These guide-pieces were up to the present th w m can b l t d accurately A 'RnSmatm: wllerefrolh resulbed a l safety pin 15 prevents thedestruction of the tlvely eXP eI1SlVe gimportant parts of the chuck in case of too Accordlng to the invention, round rods high power-of manor workpieces. f are used as guide-pieces, flattened on the The body 1- of, the chuck is made of a sin- Eeupper side to support the clamping jaws. gle piece of metal, the perimeter ofwhich 9 is of circular form, the same having a central bore or opening, and between the inner and thinner wall of the opening and the outer wall of the body there are a plurality of radial openings which are substantially circular, except where the openings extend through the face of the body, a portion of each of the openings being parallel and stepped to receive rods or slides 9. The body of the chuck is provided on one side with a stepped opening for the reception of bushings 12 and 13 for an endless screw or worm wheel 3 which is carried by the bushings, and one end of the screw or worm wheel isjkey-ended, the other end beingconvex to engage with a convex seat located in the aforesaid bore of the bushing for engagement with the convex end of the screw. The threads of the worm or screw 3 engage with a concave and threaded face of a ring 2 which has integral therewith cam flanges 4c, the opposite edges of the flanges engaging rollers 5 which are mounted upon carrying pins 6 attached to the slides 9, said slides being adjustable by means of bolts 11 that connect the stepped and reversible jaws 10 to their respective slides. j

The worm wheel 2 has on its side which is opposite to the jaws a recess in which is seated a ring that it attached to the body of the chuck by screws which enter apertures in the body located to one side of the recess in which the worm wheel is seated.

The bushing 13 is held in place by a fragile safety pin 15, and the opposite bushing 12has a flange which impinges against a shoulder formed by a reduction of the aperture in which is seated the worm 3.

In use, when the worm is turned, the cams on the toothed gear will move the slides 9,

said slides carrying with them the work clamping aws, said aws v connected to the members whlch are clamped I in adjustable position upon their respective j V worm-wheel, and

slides 9.

The construction provides for the reversal of the clamping jaws and for a'change of position thereof relative to the slidable members.

I claim:

1. A jawchuck for machine ,tools, comprising in combination a body having cylindrical borings, a worm-wheel, cams on said round rods serving as guide-pieces all accommodated in said chuck, clamping jaws on said guidepieces, connecting screws for said jaws, a roller bolt supported on both ends by two' bearings in said guide piece carrying between said two bearings of said guide-piece the roller which said worm is jo p H pressure-screw in one of said bushings andand formed 'onton e end as a collar to "support sald roller, a worm for dr v ng said worm-wheel, two, bushings in sa d body, in

urnalled, counterbeing adj ustably a safety pin connecting said bushing with said body.

2. A jaw chuck, comprising in combination a body (1), radial grooves on the one side of said body, guide-pieces (9) for the jaws received in said radial grooves, a circular groove on the other side of said body cutting into said radial grooves, a worm wheel (2) with a plurality of spaced apart eccentric flanges (41) located within said circular groove, rollers (5) on bearing-bolts (6) at both the ends of said guide-pieces, a worm-screw (3) to drive said worm-wheel and a disk supporting said worm wheel.

In testimony whereof I aflix my signature.

' WILHELM BERG. 

